The primary goal of this program is to better understand the molecular basis of thrombotic disease. To this end the group of eight clinical and basic scientists have joined together to initiate fundamental studies on blood coagulation and related phenomena. These studies include structural studies on fibrinogen and fibrin, platelet physiology and biochemistry, biocompatibility of materials and fibrinolysis and thrombin inhibition. In particular, it is proposed that the primary structure of fibrinogen be completed and the structural basis of fibrin determined, that the interaction of collagen and platelet surfaces be unraveled, that the thrombogenic nature of surfaces be investigated, and the amino acid sequence of platelet factor 4 be completed. Moreover, very promising studies on synthetic thrombolytic agents will be continued, as will be a variety of studies involving synthetic polypeptides. BIBLIOGRAPHIC REFERENCES: Doolittle, R.F., Cassman. K.G., Cottrell, B.A., Friezner, S.J., Hucko, J.T. and Takagi, T. Amino Acid Sequence Studies on the Alpha-Chain of Human Fibrinogen. Characterization of Eleven Cyanogen Bromide Fragments. Biochemistry, In Press (1977). Doolittle, R.F., Cassman, K.G., Cottrell, B.A., Friezner, S.J. and Takagi, T. Amino Acid Sequence Studies on the Alpha-Chain of Human Fibrinogen. The Covalent Structure of the Alpha-Chain Portion of Fragment D. Biochemistry, In Press (1977).